abstract contract A {
	function test() external virtual returns (uint256);
	function test2() external returns (uint256);
}
abstract contract X is A {
	function test() external returns (uint256);
	function test2() external override(A) returns (uint256);
}
// ----
// TypeError: (151-194): Overriding function is missing 'override' specifier.
// TypeError: (76-120): Trying to override non-virtual function. Did you forget to add "virtual"?